The present invention relates to an endoscopic instrument for performing endoscopic procedures or examinations, having a shaft, a handle arranged at the proximal end of the shaft, and at least one working element arranged at the distal end of the shaft, in particular mouth parts.
The invention further relates to an endoscopic instrument suite that contains such an endoscopic instrument and also a light-supplying apparatus and an endoscopic observation instrument, in particular an endoscope, that is connected to a light source.
Endoscopic instruments and endoscopic instrument suites of this kind are commonly known, and are used in the increasingly widespread practice of minimally invasive surgery.
The methods of photodynamic diagnosis (PDD) and photodynamic therapy (PDT) are increasingly being used in endoscopy to detect and treat tissue changes. The offprint from Endo World, URO No. 17/1-D, 1997, “Photodynamic diagnosis (PDD) for early detection of bladder carcinoma” [Photodynamische Diagnose (PDD) zur Früherkennung des Harnblasenkarzinoms] of Karl Storz GmbH & Co., Tuttlingen, Germany, discloses a system used, in conjunction with a photosensitizer that accumulates in tumor-specific fashion and exhibits fluorescence under specific excitation light, to detect tumors or malignant tissue changes. Aminolevulinic acid (ALA), for example, is used successfully as a precursor of a photosensitizer of this kind.
It is known from U.S. Pat. No. 5,408,996 to detect malignant tissue endoscopically by causing fluorescence of a marking substance conveyed to the tissue.
Tissue changes can also be detected on the basis of “autofluorescence” triggered by natural fluorescent substances occurring superficially in external tissue layers.
In all these methods, light (called “excitation light”) in a specific wavelength range is coupled into the tissue region containing the fluorescent substance, and that fluorescent substance is thereby excited to fluoresce. The fluorescence wavelength range is always of longer wavelength than the excitation range. When ALA is used as the precursor for the tumor-specific photosensitizer photoporphyrin, excitation is performed in the blue (380 to 340 nm), and fluorescence occurs in the red (635 nm). The manner in which fluorescent excitation, as opposed to normal or so-called “white” light, can make a tumor visible in clearly defined fashion is strikingly evident from page 5 of the aforementioned “Endo World” brochure. Even tiny satellite tumors of a fluorescing papillary tumor can be detected in a manner clearly differentiated from the principal tumor, and can be appropriately treated or removed in a surgical endoscopic procedure.
In autofluorescence examinations, the excitation can also occur in the blue and the fluorescence appears principally in the green and red spectral region. Excitation can also be performed in the UV range.
Since the fluorescence intensity is much lower than the excitation intensity, the spectral region of the excitation light is almost completely blocked out in the receiving observing system by filters, to allow detection of the fluorescent emission. Only the fluorescing areas are clearly visible.
This has the disadvantageous consequence that when instruments are introduced into the region illuminated and imaged by the endoscope, these instruments are difficult or in fact impossible to detect when the illumination system is operating in fluorescence mode. In other words, a surgeon watching the surgical procedure via an endoscope, cannot see the instrument in the fluorescence illumination mode. It has therefore hitherto been necessary to switch over continually from fluorescence mode to white-light mode, and vice versa, in order to bring an instrument accurately to the tissue area that is to be examined or treated. This is cumbersome, extremely laborious and irritating to the surgeon, and most of all hazardous or critical in terms of the procedure.
These instruments can be of many different kinds. They can be instruments used in examinations (diagnosis) or also in surgical procedures (therapy).
It is fundamentally known from DE 39 33 199 C2 to equip the distal end piece of a flexible endoscope with a marking which makes it possible to view the end piece in the context of X-ray examinations.
It is the object of the present invention to create an endoscopic instrument that is clearly detectable even in fluorescence mode, and to create an endoscopic instrument with which endoscopic surgical procedures or examinations can be performed under fluorescence conditions.